Monday, December 29, 2008

The thrust belt in my driveway

It's snowed a lot in the past two weeks. Somewhere around two feet of snow fell between the last day of classes and December 26. Good for ski areas, but a lot of work to shovel. Fortunately, structural geology can make all kinds of difficult labor fascinating.

When you push a shovel through a relatively thin layer of snow, it piles up next to the shovel in a wedge shape. Push the shovel along, and the wedge gets longer and thicker, but it maintains the same shape: a triangular wedge, with a consistent angle at its front end.

Photo: a wedge of folded and faulted snow in my driveway, 12/22/08.

You see similar shapes in belts of thrust-faulted rocks from mountain belts all around the world, from the Himalayas to the Canadian Rockies to the Appalachians to Taiwan:

The cross-section above is from a classic paper by Davis, Suppe, and Dahlgren (1983) that explains what's going on mechanically in these wedges. The shape of the wedge is governed by a balance of horizontal forces: the push from behind the wedge; gravity, which would tend to flatten out the wedge (by moving material from the higher back part of the wedge to the front); and the frictional resistance to sliding, which tends to keep the front of the wedge from sliding along, causing the wedge to be steeper. The other big assumption is that the wedge is always just about to fail: its internal strength exactly balances the stresses that compress it. This means that the nature of the material also makes a difference - cohesive sheets of material behave differently from loose sand.

There's a lot of underlying math behind the explanation of wedge mechanics, but the cool thing about it is that it all boils down to a pretty simple concept. If the friction at the base of the wedge and the mechanical behavior of the rock (or snow) stays the same, the wedge should maintain the same shape. It can get bigger, but the front of the wedge should keep the same angle. That simple geometry has a lot of predictive power. It tells what should happen in a mountain belt that's eroded by a lot of rain or glaciers, compared to one that's in a rain shadow. It's been used as one explanation for the exhumation of high-pressure metamorphic rocks. And it solved a long-standing problem for structural geology: how could huge masses of rocks slide along a nearly flat plane for immense distances, as had been observed in places like the Canadian Rockies.

And it turns snow shoveling into an analog modeling experiment. Take a driveway made of smooth concrete. Drive a truck over it, and pack down snow in parallel ridges. Then let it snow another couple inches before shoveling the driveway. The results of the experiment look like this:

The wedge started out small. It's hard to see the exact structure forming - are there thrust faults beneath the folds on that surface? But it formed a nice taper, and slid along fairly easily. (Note the highly rigorous descriptions of basal friction from this experiment.)

I pushed the shovel a bit more, and the wedge got longer and thicker, but kept the same shape:

But then I reached the old tire track, and it suddenly got really hard to push that shovel. And the wedge looked like this:

The taper of the wedge suddenly got steeper, at least until I got past the tire track. But by that time I was experiencing significant edge effects, both from the top of the shovel and the snowbank beside the driveway, so the experiment ended.

The different snow storms led to somewhat different wedge shapes. Over Thanksgiving, we had a couple inches of wet snow. It formed a cohesive layer, and I could see the individual fault blocks. (I even had some tear faults separating thrust faults with different offset! Unfortunately, I didn't have the camera yet.) Before AGU, we had an inch or so of powder, which compacted somewhat when I shoveled it. And on Christmas night, we had about five inches of wet, heavy snow, and I stopped doing experiments because moving it was a lot of work, and besides, it kept falling over the top of my shovel.

My students still think that snow is for skiing, not for experimenting with structural geology. But if you've got to shovel, you might as well have geeky fun at the same time.

Reference: Davis, D., Suppe, J., and Dahlgren, F. A., 1983, Mechanics of fold-and-thrust belts and accretionary wedges: Journal of Geophysical Research, v. 88, n. B2, p. 1153-1172.

Photo note: I adjusted the levels on all the snow photos, because I haven't figured out how to take good photos of snow with my new camera yet.

Thursday, December 25, 2008

Fresh dinosaur tracks

It's snowing. A lot. This morning, there was even a little snow on the walk under the eaves, outside my front door. And some tiny dinosaurs had been hopping there, looking for seeds in the dead plants:

Can I count this toward my list of geological things I've done?

(Also, since ice is a mineral, is snow a sediment or a volcanoclastic deposit? I know it's not metamorphic until it's been buried in a glacier, or at least buried in the snowpack and recrystallizes.)

I hope everyone has had and is having great holidays.

Friday, December 19, 2008

The stuff that comes home from a conference

I don't pick up as much stuff at conferences as I used to. I've stopped checking baggage unless I'm traveling with my kid, and I never have room to bring home books and flyers and toys. But it's hard to come home without picking up anything:

Counter-clockwise from top left: AGI's new materials for attracting students to the geosciences; my meeting program (with my scribbled notes from one session inside it); a publisher's book list; a CD from William Prothero, who spoke in my session; a free mini-fieldbook; a public transit map; a sticker from GSA; my name badge (along with a holder that I forgot to recycle); and a cool magnetic shapes game for my son (because it's never to early to learn about rotational symmetry, even if it's 7-fold).

Any suggestions as to where I should put the sticker? I'm considering my computer and my coffee cup at the moment. (The car is officially a sticker-free zone.)

(I had to use the new camera, even if it's for something that will make Chris Rowan jealous. I promise to show pictures of things like rocks or minerals soon, as penance.)

Wednesday, December 17, 2008

AGU non-blogging

I'm at AGU (after a rather eventful travel day that included a cancelled flight and a broken de-icer, among other things). I'm not live-blogging it, but maybe if I have time, I'll blog about at least one of the sessions I went to:

Early morning: Teaching Geoscience in the 21st Century posters. (Saw a few posters, had long conversations - mostly about teaching - with people I knew from the Teaching Intro Geoscience workshop. I have more ideas to steal now.)

Late morning: Exhumation of High- and Ultra-high Pressure Rocks: the cross-disciplinary view. I will blog more about this if I find the time - this is the research that I wish I had gotten into as a grad student, and which still fascinates me.

Gabbed with former thesis student. Ran into some grad school friends in the hall. (Scientists have a reputation as anti-social. It's a big lie.)

Early afternoon: Plate motion and its relation to deforming zones. I find high-precision GPS data fascinating, and wanted to learn more about it. I'm not in this field (and never have been), so I don't have a good handle on what is new and exciting (other than being able to really truly see active deformation, which is exciting enough for me). I probably won't blog in detail on it, but it was an interesting session.

Late afternoon: Teaching Introductory Geoscience: Staying Relevant in the 21st Century II. This was my session. Maybe I'll blog about what I'm doing at some point. I won't blog about the other talks, because I was busy trying to remember what I was going to say in mine. (I have this problem in sessions all the time. It's a shame, because I miss learning interesting things related to my own research interests.)

Ran into a college friend who I thought had become a biologist. Gabbed.

Had a late dinner with geology bloggers. (Scientists are social, remember.)

And now I'm here, and need to go to bed, so I can get up, have a too-short day, and run back to the airport to go home.

AGU has grown a lot since I was here last - I wish I was staying longer.

Sunday, December 14, 2008

Geologists' 100 things meme

The geologist's 100 things meme, from Geotripper.

Bold the ones you have done:

1. See an erupting volcano [Kilauea, barely oozing lava at the time, but still thrilling.]
2. See a glacier [A couple in the Alps, including the spectacular Gornergrat. One had signs showing the location of its toe through the years. It had receded a lot - and I visited it in 1991.]
3. See an active geyser such as those in Yellowstone, New Zealand or the type locality of Iceland [Yellowstone.]
4. Visit the Cretaceous/Tertiary (KT) Boundary. Possible locations include Gubbio, Italy, Stevns Klint, Denmark, the Red Deer River Valley near Drumheller, Alberta. [The local K-T boundary is an unconformity. I think. If it's not, then I've seen it.]
5. Observe (from a safe distance) a river whose discharge is above bankful stage [It was a stream, really, and it wasn't a safe distance.]
6. Explore a limestone cave. Try Carlsbad Caverns in New Mexico, Lehman Caves in Great Basin National Park, or the caves of Kentucky or TAG (Tennessee, Alabama, and Georgia [I'm fairly claustrophobic, so I've only been into caves with lights and tours and stuff. Most recently, Lehman Caves, which are beautiful.]
7. Tour an open pit mine, such as those in Butte, Montana, Bingham Canyon, Utah, Summitville, Colorado, Globe or Morenci, Arizona, or Chuquicamata, Chile. [The most impressive was the Homestake Mine in South Dakota, which I visited on an undergrad field trip.]
8. Explore a subsurface mine. [As a tourist, in the Upper Peninsula of Michigan most memorably.]
9. See an ophiolite, such as the ophiolite complex in Oman or the Troodos complex on the Island Cyprus (if on a budget, try the Coast Ranges or Klamath Mountains of California). [Coast Range ophiolite.]
10. An anorthosite complex, such as those in Labrador, the Adirondacks, and Niger (there's some anorthosite in southern California too). [The Adirondacks.]
11. A slot canyon. Many of these amazing canyons are less than 3 feet wide and over 100 feet deep. They reside on the Colorado Plateau. Among the best are Antelope Canyon, Brimstone Canyon, Spooky Gulch and the Round Valley Draw.
12. Varves, whether you see the type section in Sweden or examples elsewhere. [Remnants of Glacial Lake Vermont. Not a good place to chew silt and clay - there was a cow pasture above the exposure.]
13. An exfoliation dome, such as those in the Sierra Nevada. [Yosemite.]
14. A layered igneous intrusion, such as the Stillwater complex in Montana or the Skaergaard Complex in Eastern Greenland.
15. Coastlines along the leading and trailing edge of a tectonic plate (check out The Dynamic Earth - The Story of Plate Tectonics - an excellent website). [Japan, and the coast of Maine.]
16. A gingko tree, which is the lone survivor of an ancient group of softwoods that covered much of the Northern Hemisphere in the Mesozoic.
17. Living and fossilized stromatolites (Glacier National Park is a great place to see fossil stromatolites, while Shark Bay in Australia is the place to see living ones) [Upper Peninsula of Michigan.]
18. A field of glacial erratics [Do the woods behind the house where I grew up in Maine count?]
19. A caldera [Long Valley, Yellowstone, Silverton, Lake City...]
20. A sand dune more than 200 feet high
21. A fjord [Technically Somes Sound in Acadia National Park is a fjord.]
22. A recently formed fault scarp [Borah Peak earthquake.]
23. A megabreccia
24. An actively accreting river delta [There are small ones into every reservoir around here.]
25. A natural bridge
26. A large sinkhole
27. A glacial outwash plain [Where the glaciers in the Alps were receding.]
28. A sea stack [Coast of Oregon.]
29. A house-sized glacial erratic [In the woods in Maine.]
30. An underground lake or river
31. The continental divide [Only the Atlantic-Pacific one in the US. But I have to cross it all the time.]
32. Fluorescent and phosphorescent minerals [Only in museum displays.]
33. Petrified trees [Only in the department rock collection; not in the field.]
34. Lava tubes [Hawaii.]
35. The Grand Canyon. All the way down. And back. [Only from the rim.]
36. Meteor Crater, Arizona, also known as the Barringer Crater, to see an impact crater on a scale that is comprehensible [Only from the air.]
37. The Great Barrier Reef, northeastern Australia, to see the largest coral reef in the world.
38. The Bay of Fundy, New Brunswick and Nova Scotia, Canada, to see the highest tides in the world (up to 16m)
39. The Waterpocket Fold, Utah, to see well exposed folds on a massive scale.
40. The Banded Iron Formation, Michigan, to better appreciate the air you breathe.
41. The Snows of Kilimanjaro, Tanzania,
42. Lake Baikal, Siberia, to see the deepest lake in the world (1,620 m) with 20 percent of the Earth's fresh water.
43. Ayers Rock (known now by the Aboriginal name of Uluru), Australia. This inselberg of nearly vertical Precambrian strata is about 2.5 kilometers long and more than 350 meters high
44. Devil's Tower, northeastern Wyoming, to see a classic example of columnar jointing
45. The Alps.
46. Telescope Peak, in Death Valley National Park. From this spectacular summit you can look down onto the floor of Death Valley - 11,330 feet below.
47. The Li River, China, to see the fantastic tower karst that appears in much Chinese art
48. The Dalmation Coast of Croatia, to see the original Karst.
49. The Gorge of Bhagirathi, one of the sacred headwaters of the Ganges, in the Indian Himalayas, where the river flows from an ice tunnel beneath the Gangatori Glacier into a deep gorge.
50. The Goosenecks of the San Juan River, Utah, an impressive series of entrenched meanders.
51. Shiprock, New Mexico, to see a large volcanic neck
52. Land's End, Cornwall, Great Britain, for fractured granites that have feldspar crystals bigger than your fist.
53. Tierra del Fuego, Chile and Argentina, to see the Straights of Magellan and the southernmost tip of South America.
54. Mount St. Helens, Washington, to see the results of recent explosive volcanism.
55. The Giant's Causeway and the Antrim Plateau, Northern Ireland, to see polygonally fractured basaltic flows.
56. The Great Rift Valley in Africa.
57. The Matterhorn, along the Swiss/Italian border, to see the classic "horn".
58. The Carolina Bays, along the Carolinian and Georgian coastal plain
59. The Mima Mounds near Olympia, Washington
60. Siccar Point, Berwickshire, Scotland, where James Hutton (the "father" of modern geology) observed the classic unconformity
61. The moving rocks of Racetrack Playa in Death Valley
62. Yosemite Valley
63. Landscape Arch (or Delicate Arch) in Utah
64. The Burgess Shale in British Columbia
65. The Channeled Scablands of central Washington
66. Bryce Canyon
67. Grand Prismatic Spring at Yellowstone
68. Monument Valley
69. The San Andreas fault

70. The dinosaur footprints in La Rioja, Spain
71. The volcanic landscapes of the Canary Islands
72. The Pyrennees Mountains
73. The Lime Caves at Karamea on the West Coast of New Zealand
74. Denali (an orogeny in progress)
75. A catastrophic mass wasting event [Not in progress, but recent.]
76. The giant crossbeds visible at Zion National Park
77. The black sand beaches in Hawaii (or the green sand-olivine beaches)
78. Barton Springs in Texas
79. Hells Canyon in Idaho
80. The Black Canyon of the Gunnison in Colorado
81. The Tunguska Impact site in Siberia
82. Feel an earthquake with a magnitude greater than 5.0.
83. Find dinosaur footprints in situ
84. Find a trilobite (or a dinosaur bone or any other fossil)
85. Find gold, however small the flake

86. Find a meteorite fragment
87. Experience a volcanic ashfall
88. Experience a sandstorm
89. See a tsunami
90. Witness a total solar eclipse
91. Witness a tornado firsthand. (Important rules of this game).
92. Witness a meteor storm, a term used to describe a particularly intense (1000+ per minute) meteor shower
93. View Saturn and its moons through a respectable telescope.
94. See the Aurora borealis, otherwise known as the northern lights.
95. View a great naked-eye comet, an opportunity which occurs only a few times per century
[I've seen the Northern Lights and one of the spectacular comets of the 1990's at the same time. Possibly the most amazing thing I've ever witnessed.]
96. See a lunar eclipse
97. View a distant galaxy through a large telescope
98. Experience a hurricane [A small one. I didn't know at the time that "typhoon" and "hurricane" were the same things.]
99. See noctilucent clouds
100. See the green flash

There are several of these that I haven't done, but which I could do within a day's drive of my house. Kind of embarrassing - I've lived here longer than I've lived anywhere but Maine, by this point.

Saturday, December 13, 2008

My five-year-old is losing his apatite

My five-year-old has cavities. Four cavities. Two on his lower left, where his back teeth rub together, and two little ones in the same spot on his lower right and upper left. I've never had any cavities myself, so I may be more worried about the next dental visit than he is.

"Does he drink a lot of juice?" the hygienist asked me.

"No..." I frowned. "But I've been letting him brush his teeth himself. He might not be doing a very good job."

"The chewing surfaces look fine," the hygienist said. "He's got to get the sugar between his teeth to get his cavities. Usually it's fruit juice that does it."

"He drinks mostly milk and water," I said. "What else could it be? We don't do very good job flossing his teeth, I know. And... we were on well water until this summer. I never got the water tested for fluoride, and the dentist didn't want to give him extra fluoride, because the groundwater around here varies alot." I didn't go into detail about the diverse bedrock geology that contributes to the variability in water chemistry. I was busy feeling guilty because I had treated the problem as something to solve by knowing more about the bedrock, when I should have just sent the water to the local health department for a fluoride test.

See, I don't know much about teeth, except that brushing and flossing every day is good, eating lots of sugar is bad, and the enamel coating consists mostly of the mineral hydroxyapatite. And that tooth decay happens because sugar-eating bacteria excrete weak acids, which slowly etch the hydroxyapatite and destroy the enamel.

Apatite is a mineral that all geologists learn at least in passing – it defines “5” on Moh’s hardness scale, it’s the most common of the phosphate minerals, and it’s got a funny name. And it’s present in a lot of different types of rocks, igneous, sedimentary, and metamorphic. I usually miss it when glancing at a thin section, but find it on a microprobe, when I’m actually looking for tiny grains of plagioclase feldspar. But most of what I know about apatite comes secondhand, from collaborating with thermochronologists, who use apatite to figure out when rocks cooled to near-surface temperatures. (Well, that’s near-surface to someone who likes to work on metamorphic rocks.)

When I was in grad school, apatite was mostly used for apatite fission-track dating*. Apatite is mostly a calcium phosphate mineral, but it can contain tiny amounts of uranium. When the uranium decays by nuclear fission, it damages the crystal lattice of its host apatite grain. If the temperatures are high enough, the lattice is able to heal, but at low temperatures, the apatite grain collects these damage zones called fission tracks. You can’t see the fission tracks in a normal thin section – you need to separate the apatite grains, mount them in epoxy, polish them, and etch the surface with an acid. Then the heroic (and very patient) thermochronologist counts and measures all the little etched tracks. But there are complications. And one of those complications has to do with the amount of fluorine that substitutes for the hydroxy (OH-) ions in the structure.

I don’t remember exactly what the complication was. But I’m willing to bet that fluorapatite isn’t just harder than hydroxyapatite. I’m not sure, but I think that fluoroapatite doesn’t dissolve as easily in acid.

My son's cavitities are in baby teeth, which is a good thing. They will fall out before enough fission tracks can accumulate in them to be countable. They will fall out and be replaced by adult teeth. Which are currently growing. Which is why the dentist prescribed supplementary fluoride tablets, for a little while, at least.

In the meantime, the hygienist and I came up with another hypothesis for the source of the sugar.

“Ummm,” I said. “When he started kindergarten, he was able to choose from white milk or chocolate milk. I think he drinks chocolate milk a lot.”

“Chocolate milk has sugar in it,” she nodded.

In fact, I think he’s been drinking chocolate milk nearly every day since starting kindergarten. I had encouraged him to try the white milk, and to save the chocolate milk for special occasions. But, well, he’s five. There are a lot of special occasions.

But now, maybe he’ll listen to me when I tell him that chocolate milk will destroy his apatite.

* Since I left grad school, a new method, (U-Th)/He dating, has been developed and become an incredibly powerful tool for thermochronology.

Friday, December 12, 2008

What does a scientifically literate person need to know about the geosciences?

What, exactly, are the earth sciences about, anyway? Even using the name "earth sciences" is a way of waffling - geology, geophysics, and geochemistry obviously fit, but what about paleontology, the oceans, climate, the atmosphere, other planets...? I don't have a clear answer for myself (although I should - I teach the only college-level Earth Science course that some future K-6 teachers take), but NSF has brought together a group of earth scientists to figure it out. They've put together a draft document, opened it for one round of comments in October, and now (starting December 15) they are looking for comments on the final draft. The draft itself (and links to a page for commenting) is available here: The Earth Science Literacy Initiative.

Here are the nine Big Ideas that they have proposed:

1. Earth science explores our planet.
2. Earth is 4.6 billion years old.
3. Earth is a complex system of interactions between rock, water, air, and life.
4. Earth is a continuously changing planet.
5. Earth is a water planet.
6. Life evolves on a dynamic Earth and continuously modifies Earth.
7. Humans depend on Earth for resources.
8. Humans are threatened by Earth's natural hazards.
9. Humans have become a significant agent of change on Earth.

The meat of the document comes in the supporting statements within each Big Idea. Check it out and comment (starting Monday).

There will also be three sessions at AGU where you can discuss it:

Monday 2:10 - 2:25 pm, Room MC 3011:
Oral Session ED13D: Earth Science Literacy: Building Community Consensus

Tuesday 8:00 am, Hall D:
Poster ED21A-0601: Earth Science Literacy: Big Ideas and Supporting Concepts

Thursday 6:15 pm, Moscone West 3005
Open Town Hall Meeting: Developing a Framework for Earth Science Literacy

(H/T Barb Tewksbury.)

Wednesday, December 10, 2008

Can't go to AGU? Here are some ways to get your fix.

Not going to be in San Francisco next week? Don't want to miss out on the American Geophysical Union meeting? Here are some other ways to keep up with what's going on:

AGU will have live webcasts of one or two sessions each day:

Monday, 15 December,
0800h–1000h, U11C - MESSENGER at Mercury: The Second Flyby I

0830h–1930h, U15A - Frontiers of Geophysics Lecture: The Spread of Scientific Knowledge From the Royal Society to Google Earth and Beyond

Tuesday, 16 December
1020h–1220h, U22B - The Great 2008 Wenchuan Earthquake: A Multidisciplinary View II

Wednesday, 17 December
0800h–1000h, U31B - Episodic Tremor and Slip I: Field Studies; A Growing Cottage Industry

Thursday, 18 December
1020h–1220h, U42B - Interaction of Earth Reservoirs

Friday, 19 December
1020h–1220h, H52B - Arsenic and Other Metals as Contaminants in Hydrologic Systems

(I may have to turn on the Mercury session on Monday morning while I'm frantically writing my final exams. Planetary geology is just plain amazing.)

For commentary, Erik Klemetti may try live-blogging from his new iPod. And last year, one of the RealClimate contributors live-blogged some of the climate sessions - I don't know if they're planning to do the same thing this year. As for me - I'm not going to try to blog the meeting; I learned at GSA that I would rather talk to people face-to-face when I've got the chance. If I see anything that I want to share, I'll try to post about it later. (I blog on a geologic time scale anyway, so I figure that I can keep talking about things I saw at this year's meetings for the next billion years or so, right?)

Tuesday, December 9, 2008

Goals for the next year

It's still the beginning of December, and I know the tradition is to review the last year before AGU, and do resolutions after. And the geoblogosphere is doing the first-post-of-the-month meme. But it's not just the beginning of the last month, the end of classes, and the week before AGU for me. It's also my 42nd birthday, and in celebration of the number 42 and the answer to life, the universe, and everything, I'm going to skip straight to plans for the next year.

In the next year I want to:

- Put more miles on my bike, skis, and feet than I do on my car. ("Better start taking long bike rides," says my husband. Bad news, because I prefer to run. But I was doing 20-mile weeks a few years ago while training for a marathon; I would like to get back to that kind of mileage.) If I can't pull it off, I want to at least do two running races: the Mother's Day 10K trail race (with free chocolate) and the Thanksgiving Day Turkey Trot. Both start within a bike ride's distance of my house, too.

- Get one paper sent off to a journal. I know this doesn't sound very ambitious, especially for people who are still actively in the job hunt. But for me, it's more about not feeling guilty than about being a super-productive scientist. Finish the paper, stop feeling lousy about myself.

- Follow through on at least one really crazy idea. Could be a research idea, could be a teaching idea, could be some kind of non-work thing that I'm scared to try. (Husband says I should do this 42 times, but when I say follow through, I mean really follow through. It could take a year or more to really give a crazy research or teaching idea a chance.)

- Avoid unpleasant interpersonal politics. I've been lucky this year - I've been on good committees, my department is getting along, and the geoblogosphere has been pleasant. I'm going to try to continue the pattern.

- Post more pictures. I got a new camera for my birthday. Now I need to learn how to use it (and how not to break it).

Oh, and unrelated: for an AGU meetup, how about at the Thirsty Bear (661 Howard St., SF) at 7:30 pm on Wednesday, December 17?

Geobloggers at AGU

Geobloggers (and anyone else who wants to come) are planning to get together on Wednesday night (one week from tomorrow!) at AGU. And... well, we haven't made any plans beyond that. Let's make some.

Here are my constraints: I'm giving a talk that ends at 5:30 pm, and my session ends at 6. (And it would be kind of rude to give my talk and run.) I think Brian's session is earlier in the afternoon?

I don't have any suggestions for where to meet - I haven't been to San Francisco since 1999 (which wasn't even this century, and yes, that does make me feel old, especially today). Apparently the Moscone Center is twice as big as it used to be, too. So Bay Area locals (Brian? Andrew?) - any suggestions for a time and place? AGU has also gotten even larger in the past nine years, so I'm guessing that restaurants are hard to find (except that San Francisco should still be better than Houston after a major hurricane... well, unless there's an earthquake this week, which I most fervently hope there is not).

Edit: How about the Thirsty Bear at 7 pm?

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Sunday, December 7, 2008

Old dogs and new tricks

I've just realized that I'm going to be giving my first AGU talk (ever) in a week and a half.

It's actually kind of scary, even though I've spent way too many person-hours talking to darkened rooms in my career. (And even though I'm not going to be trying to impress potential employers; this will be my first AGU meeting when I don't need to look for a job.)

Saturday, December 6, 2008

Field work: this might be heaven or this might be hell

I love field work. No, really, I do. But when I tell stories about it, they always end up being about running out of food or wrecking vans or collecting samples of giant mosquitoes by slamming a field notebook shut or not being able to find a single sample of high-pressure metamorphic minerals except trapped as inclusions in a garnet. (And that was just my PhD area.) I've thrashed through ice-storm-damaged woods, taking an hour to walk a mile, in search of non-existent staurolites. I've fallen into streams. I've broken a canoe paddle while trying to cross a melt-swollen river. I've post-holed through snow banks. I come back from the field covered in mud, sweat, scratches, bruises, and occasionally blood from where my hammer missed the chisel and slammed the back of my hand.

Which makes me wonder, while lying in a tent with an aching back and wondering whether that sound outside is a hungry bear or just a vole with insomnia, whether it's worth it.

Then I come back to the human world, where people care about things like other people's shoes*, and I think: worth it? Are you kidding?

Photo: me, someplace where the temperatures are cold and the rocks are hot. In other words: someplace close to heaven.

(For the November Accretionary Wedge.)

* Edit: a story, in explanation. In my second or third year in my previous job, I was a junior faculty member on one of those campus-wide committees. Before one snowy winter meeting, I found myself outside the meeting building with the committee chair, a faculty member in another department on campus. She said to me: "Isn't the etiquette of Vermont winters funny? It's inappropriate to look at other people's shoes until they've had a chance to change them." I was flustered and had no idea what to say; I generally changed into indoor shoes because my winter boots were snow-covered, muddy, and made my feet sweat. It had never occurred to me that I was being judged by my footwear.

I failed to successfully negotiate the social boundaries between effective teaching, interesting research, and the expected image of a female faculty member. My favorite field area was in northeastern Vermont - although it was in dense, bug-filled woods, it was the first place where I found surprising results and struggled through to models that were my own, not my advisor's or another mentor's. And I haven't been back there since I was denied tenure.

I've found a new, beautiful place to work. I haven't had the thrill of finding things that are unexpected yet. But there are beautiful views, and in Durango, nobody cares what I wear.

Thursday, December 4, 2008

National Student Exchange

Fort Lewis College has recently re-joined the National Student Exchange, a program that allows students at many colleges and universities in the US and Canada to study at another institution in North America. Geology students usually get to study in another part of the continent (or sometimes the world) during field camp, but NSE makes it possible to spend an entire year in another geologic setting.

Most of the schools that participate are public colleges and universities. There's a complete list on NSE's web page. If anyone is interested in coming to Durango for a year and wants information about how the geology courses at Fort Lewis would fit into their home institution's major, please feel free to contact me. (shearsensibility AT gmail DOT com, or in comments, or by googling my name and sending me an e-mail at work).

Opportunities for grad students interested in working in national parks

From a friend who now works for the National Park Service: Park Break.

If you're a grad student interested in a career working in a national park, you can spend spring break learning about national park management and research careers. Park Break is designed to give graduate students experience that could lead to work in a national park. And for geoscience students, it could lead to a summer internship through the GeoCorps program.

Applications for Park Break are due by December 31, and applications for the GeoCorps program are due by January 31.

Tuesday, December 2, 2008

Experience with non-PV solar technology?

Does anyone out there have experience working with non-photovoltaic solar technology? Anything from the theoretical to building your own solar hot-water heater? I've got a writer friend who is working on an article on solar thermal technology. She's especially interested in talking to people who have experience with small-scale projects (like a water system for a home), but she's interested to talking to anyone who can help her understand the background, too.

I vaguely remember talking about semi-off-the-grid ideas when I was in high school. (A friend had an indoor swimming pool that may have been partly solar, but I think it was also heated by a wood stove. That was Maine, and the sun doesn't shine as much there as it does in Colorado.) But although I know people from grad school who rebuilt diesel engines to run on used cooking oil, it's been a long time since I've talked to anyone who does their own passive solar. (Beyond south-facing windows, that is.)

If you've got experience or know people who do, could you e-mail me (shearsensibility AT gmail DOT com), so I can pass contact information along to my friend?

Monday, December 1, 2008

How important are GRE scores for geoscience grad school?

I took the GREs twenty years ago this month. Twenty years! I spent an entire day of my Christmas break in a big lecture hall at the University of Maine, filling in bubbles with my #2 pencil.

The world has changed in the past twenty years. GREs are taken on computers these days, and the bizarre but fascinating logic problems are gone. ("Jenny likes cabbage, but Fred is allergic to horseradish. Who is seated beside Louise?") There's a new writing section, along with the verbal and math sections. And there's no longer a geology subject test. So I've become less and less capable of giving any kind of reasonable advice to students about how to prepare for it. And because I don't read grad student applications, I don't have any idea how grad schools look at the current version of the test.

When I started grad school, I got the impression that the GREs weren't particularly important for anything except competing for NSF graduate fellowships. Research is not a multiple choice exam, and the ability to fill in little bubbles (or whatever mouse-click has replaced it) is no substitute for creativity, perserverence, and the ability to take a lot of criticism. I've gotten the impression that the things that matter for a graduate application are 1) a coherent statement of purpose that fits with the research interests of a faculty member; 2) good grades in relevant coursework (maybe geo, maybe math or chemistry or physics); 3) strong letters of recommendation; and 4) maybe research experience, although it's become common enough at the undergraduate level that it might not mean as much these days unless it's incorporated into the statement of purpose. The GREs - well, the general test is taken by everyone, from physicists to literary scholars, and it would be hard to come up with a test that could identify people who would be skilled at both subjects. I remember the verbal section as being essentially the SATs with longer words (but not geology jargon), and the math section as being algebra. I took it, I sent off the scores, and I never thought about the test again*. Until students came to me worrying about it.

So here's my question to the rest of the world. Based on your experience, do GRE scores matter? Do some schools put more weight on them than others? Is there a minimum cutoff score for some schools, or are they used as a tie-breaker between otherwise similar applications? Or are they a form of practice at jumping through hoops, preparation for things like dissertation formatting instructions?

*Well, other than to score geek points against my soon-to-be-ex college boyfriend. But once I got to grad school, I didn't think about the scores.

Wednesday, November 26, 2008

My research history, in time and P-T

I like Chris Rowan's idea of placing his research on a geologic time scale, so I stole his image and edited it:

Since I did some geochronology (actually, a major part of my PhD was explaining that it was impossible for my data to be meaningful), I felt like I should include the bad data as well as my preferred ages for events.

But the time scale doesn't have enough dimensions for my research, so here's version in pressure-temperature space.

All the green is actual data from Vermont. The blue arrow is supposed to represent my PhD work, except that the rocks were really lousy for finding any kind of data, and I didn't work on the low-pressure ones that told a better story. The red is Colorado, both my senior thesis and current work with senior thesis students. The yellow is one rock deformation experiment that a couple of my undergrad students in Vermont did one summer. And I figured if I was going to include the really low-pressure stuff, I ought to include the water quality stuff I've advised, but it doesn't really fit on the diagram.

Monday, November 24, 2008

Ophiolites and ocean crust: slow tectonic shifts in textbook science

For more than fifteen years, I've been making my Plate Tectonics students read Assembling California by John McPhee. In part, I'm just using my dastardly professorial powers to inflict one of my favorite writers on helpless students. In part, I just want students to read lines like "You need a new geologist. You need a Californian." But mostly, I want students to think about ophiolites and the ways that scientists change their minds.

All of the textbooks that I've used simplify the ophiolite sequence in the same basic way. It's oceanic crust, stranded on land where we can see it and touch it and measure its structures and sample its minerals. Sediments, pillow lavas, sheeted dikes, massive gabbro, layered gabbro, layered peridotite, deformed mantle rock. The field geologist's answer to the layers recognized by seismologists on the ocean floor. The record of sea-floor spreading, one of the many pieces that fell into place as plate tectonic theory came about.

Getting that ocean floor onto continents where geologists can study it without submersibles or seismic waves is tricky. I remember arguing about California's Coast Range Ophiolite with my officemates (probably at Friday Beer after the high-pressure-metamorphism seminar). It's inland of the old subduction complex of the Franciscan Formation, so did that mean that it represented the closure of an old ocean basin? Or was it shoved up onto the continent as some kind of flake? Or, well, how do you do that mechanically, anyways? (Big picture tectonic arm-waving works better after beer. Increase pore fluid pressure and all that.)

Sometime in those nineteen years during since that seminar, the consensus understanding of ophiolites has changed. It hasn't been something that makes headlines, but in study after study, it's turned out that the trace element geochemistry has the wrong fingerprints for the ocean floor. Most ophiolites - even the famous ones like Troodos on Cyprus or the Semail ophiolite in Oman - most ophiolites formed above subduction zones.

I had heard rumors about this from igneous geochemists before, but an article in last month's GSA Today went further. If the geochemistry says that ophiolites aren't rocks that formed at mid-ocean ridges, well, we really shouldn't be using them to study what happens at mid-ocean ridges. We can't even use the sheeted dike complexes - sheets of cooled magma that intruded one another so that only half of any original dike is left - to talk about sea-floor spreading. At mid-ocean ridges, the rates of magma production and spreading are tied together, but above subduction zones, they're the result of two different processes. It's possible for the plate above a subduction zone to spread, if the downgoing plate sinks faster than the over-riding plate slide across it. (That's happening, for instance, near the Mariana Trench. And it's one of those complicating bits of tectonics that doesn't match the stories that get told in introductory classes, and that can serve as a GOTCHA! for partly-informed skeptics. But we know about trench rollback, and it's been incorporated into geologists' understanding of tectonics for a couple decades, even if we don't explain it that well to students.) The spreading of the over-riding plate might look like a mid-ocean ridge in the rock record - it's all extensional tectonics, after all - but the relationship to magmatism is different. Not the same relationship, not the same process. Still interesting... but not a way to study the way that oceans grow. Sorry.

So touching an ophiolite isn't touching a bit of old ocean floor, after all. And we don't need to argue about how the rocks got on top of the subduction complex if they usually are formed there. And a lot of tectonic arm-waving was for naught.

And the textbook science changes.


Robinson, P.T., Malpas, J., Dilek, Y., and Zhou, M., 2008, The significance of sheeted dike complexes in ophiolites: GSA Today, v. 18,. p. 4-10. (Available for free online here.)

Thursday, November 20, 2008

Random demographic graphics

I've just installed Office 2008 on my Mac in the hopes that it would make it easier for me to read files that people send me from PCs at work. So far, I've discovered that the Mac and PC interfaces are not at all the same, which explains why my students have been so frustrated when they've tried to do assignments on their home computers.

I'm going to get familiar with Excel by graphing the demographic data from the closed survey on my sidebar. Warning: includes default color schemes and gratuitous 3D pie charts.

Two-thirds of my readers are younger than me. That doesn't surprise me, but it means that I can't make Usenet jokes and expect people to get them. It also may explain this:

Well, not exactly. It looks like the quadrant compass is going the way of Usenet and geosynclinal theory. We're gradually replacing our quadrant compasses as they break... but I'm still going to make all my students convert all their measurements back and forth, because I'm a Big Meanie.

(Also, doesn't that graph look like it ought to have "One ring to rule them all..." inscribed on it?)

The next two graphs should have an axis labeled "number of responses" - I thought the total number of each of these was more interesting than the percent.

I'm not sure if "employment" is the right title for this graph. (I'm also not sure how many of the grad students also described themselves as employed in academia.)

Edit - By the way, "pre-college" is short for "pre-college educator" here. I was curious how many people were K-12 (or earlier) teachers, especially because Earth Science isn't taught in high school in many states (including Texas and California).

And finally, I have no idea why this bar graph insists on putting "other background" on top of "geoscientist." Perhaps it knows that geoscientists are down to earth, or something lame like that.

I know that this pair of questions left out some possibilities. (People who became geoscientists after a background in something else; people who majored in geology but got a job doing something different.)

And now I can delete those surveys from the side of this blog.

Wednesday, November 19, 2008

Field nightmare

I dreamed about teaching field camp last night.

I've taught field camp in several places, but one of my favorites is near Hoback Junction, Wyoming. We camp in this Forest Service campground with views of the Wind Rivers and a hot spring just up the road. The road up to it was in bad shape last time I stayed there, but it's still a gorgeous spot.

The problem with the campground, at least the last time I stayed there, was that you can't make reservations ahead of time, and there's no group site, so it's possible that we won't find a good spot for all the students to camp near one another.

And that's how my dream started. We got to the campground fairly late, only to find that three-quarters of it was closed off with deep piles of snow still on the ground, and all the remaining sites already filled. We drove around looking for a spot, and ended up trying to turn around somewhere down at the end of one of the campground loops.

And that's where we met the RV. It wasn't just any old RV. It was... well, it was immense. Bigger than an 18-wheeler. Tougher than a tank. And driven by someone who didn't look where he or she was going.

The RV was headed straight for my Subaru*. And it didn't stop.

In the end, my Subaru was crunched to half its original length. (I woke up before considering the possible analogy between shortened Subarus and regional strain analysis of collisional tectonic belts.)

So: academic nightmares by geology professors. (At least I didn't dream that I showed up for field work a day late, with no clothes, and sat on a cactus.)

*Don't ask me why I was driving my Subaru at field camp. Normally I drive a 15 10-passenger van loaded with students and gear. And, yes, I have a complicated history with vans, which many people can tell stories about. But there wasn't a van in this dream.

Monday, November 17, 2008

Geology and science fiction: what do I think?

I'm finally mostly caught up on work, so I can answer Peggy's questions about science and science fiction.

Questions for Science Bloggers

* What is your relationship to science fiction? Do you read it? Watch it? What/who do you like and why?

Yes, I read and watch science fiction. I've enjoyed it since I was a kid, probably because I found other worlds interesting. (Especially in comparison to the sort of petty interpersonal politics that dominated grade school, junior high, and high school.) I was fascinated by big and different.

As an adult, I like stories that imagine societies different from ours. Science fiction (and also fantasy) seem like great ways to explore human-ness by imagining what happens if things were a little different. Maybe the difference is some kind of technology. Maybe the difference is a cultural attitude. In a way, it's like experiments in science.

* What do you see as science fiction's role in promoting science, if any? Can it do more than make people excited about science? Can it harm the cause of science?

I don't think science fiction is particularly good at promoting science. (One word: Frankenstein.) An awful lot of science fiction seems to reveal a fear of the unknown, a fear of tampering with nature or with going too far in trying to understand something. It's not true of all science fiction (or fantasy), but I've seen it in places as different as Tolkien and the new Dr. Who.

Whether it harms the cause of science... well, honestly, I don't think that science should be a cause, really. Science is a sort of organized curiosity about the natural world, and it's sad to live amongst people who are uncurious and afraid of learning new things. But the introspection can be a good thing, as long as it doesn't become some kind of trite repetition of the story of the Tree of Knowledge.

* Have you used science fiction as a starting point to talk about science? Is it easier to talk about people doing it right or getting it wrong?

Geology is rarely explicitly part of science fiction. (Any time a different world is imagined, geology could be used to build a world that makes sense. I've rarely seen an imaginary world that makes geologic sense, unfortunately.) Off the top of my head, I can think of only one set of books that does geology well (Red Mars, Green Mars, and Blue Mars by Kim Stanley Robinson), and I have yet to run across a student who is familiar with them.

As for movies: I guess The Core could count as a science fiction movie (as well as a bad disaster movie). I've encouraged students to watch it and criticize the geology, but it's so goofy that it's difficult to get much science from it. I haven't seen the new Journey to the Center of the Earth, but I've watched the old version with geology students. Again, it was fun to laugh at it, but it was so wrong that it was hard to know where to start with a critique. And I mention The Day After Tomorrow in class to try to explain why the textbook talks about deep ocean currents in the context of climate, but mostly we end up laughing about Jake Gyllenhaal running away from wolves in New York rather than critiquing the science in detail.

* Are there any specific science or science fiction blogs you would recommend to interested readers or writers?

Anyone who wants to read more about geology should just subscribe to Chris Rowan's geoblogosphere feed, and choose their favorite blogs for themselves.

Friday, November 14, 2008

Geology, fiction, and science fiction

A post of links, because I'm trying to get some intro exams graded:

Magma cum laude has a great post discussing the portrayals of volcanoes in several books. And Biology in Science Fiction and Almost Diamonds are asking scientists and science fiction writers some questions in preparation for a panel at the ScienceOnline 09 conference. I think the discussions could be linked, easily.

Meanwhile, Erik Klemetti reminds us that real volcanoes can be as dramatic and tragic as fiction in his remembrance of the 23rd anniversary of the destruction of Armero, Colombia. And for science fiction writers who want to put a good subduction zone into their books, Brian Romans has a detailed three-part debunking of subduction denialists, which has led to a call for posts about geologic pseudoscience.

Wednesday, November 12, 2008

A not-quite-geology haiku

There's geology haiku meme going around. I'm doing lab work today. Or, well, trying. This isn't very haiku-like, but it reflects my day:

Time for some data -
the spectrometer is warm
but the shear gas won't flow.

Tuesday, November 11, 2008


Tonight's bedtime story was Where the Wild Things Are. My five-year-old is beginning to read words, so he wanted me to show him the words on the cover.

They're all in capital letters:


"That's shouting," my son said.

"Huh?" I said. I mean, there was some shouting earlier (thus the book), but we hadn't been shouting right then.

"The letters. That means shouting."

"Did your dad tell you that, or did you learn it at school?"

"My teacher told me. All capital letters means shouting."

They're teaching netiquette in kindergarten. (Maybe he'll learn not to feed the trolls, too. Either that, or they will start making LOLcats in art class.)

Monday, November 10, 2008

Wait! Field season isn't done yet!

Well, actually, I guess it probably is for this year:

(image deleted, because I screwed up my saving and linking)

There are two inches of snow on the ground. (I would take a picture, but I still don't have a camera.) Total daytime accumulation of 1-3 inches is expected, according to the National Weather Service. More snow possible tonight and tomorrow morning, and a mixture of rain and snow tomorrow afternoon.


Except my mapping class is still mapping. And some of them didn't start the most recent map, because they were voting last week.

The high temperatures are supposed to be above freezing today and tomorrow, so maybe it will all melt down here. Or maybe I'll need to go into the field next week, and talk about the cross-sections and the report this week (before some people have done their mapping).

I would make jokes about global warming going away, but someone would probably take them seriously. (Snow in late October or early November isn't that unusual here at 7000 feet.)

Sunday, November 9, 2008

Thinking through carbon sequestration

I've been trying to figure out what to say to my classes about carbon sequestration. As Brian mentioned in a comment, if we're going to lock carbon dioxide in rocks (well, artifically*), geologists are going to need to be involved.

I ought to be able to think through the problem from first principles. Carbon dioxide is part of all sorts of natural systems, after all. When it dissolves in water, it makes the weak acid that is responsible for much of the natural weathering of silicate minerals. It's released by metamorphic reactions, and the relative amounts of carbon dioxide and water in metamorphic fluids is important in determining which minerals are stable. It's one of several gasses that dissolve in magmas, and is important in its own ultra-weird magmas: carbonatites, which erupt molten baking soda in the East African Rift (and which concentrate rare earth elements in old deposits). At low temperatures, carbon dioxide, carbonic acid, bicarbonate, and carbonate ions make a fascinating buffer system. (I don't think I explained that one very well, the one time I taught environmental geochemistry. But it's still a fascinating system.)

And that's just the chemistry. There are also questions about fluid flow through rocks and fractures, and about possible rock fracture associated with high fluid pressures. It's hard to know exactly where to start, especially because the info sources that I've read don't try to explain things from first principles.

So how, exactly, is this carbon sequestration supposed to work, and how does it relate to all the various CO2 factoids that I've accumulated over time?

The answer depends on the rock and fluid involved, it seems. A number of possible environments have been proposed, and the issues are somewhat different for each one.

1) Use waste CO2 to enhance recovery of oil and gas. I was vaguely aware that carbon dioxide was used to help recover more oil from old oil fields (mostly because CO2 is produced near Durango - it's actually a commercially produced commodity). I didn't know much about how it works, though - was it used to increase the fluid pressure in the rock, and force the oil out, or did the CO2 dissolve in the oil and change its properties? It turns out that both happen. Yes, the carbon dioxide changes the fluid pressure. But it also dissolves in the oil and makes it flow more easily, which makes it possible to recover more of the oil.

This is already being done - in fact, carbon dioxide is produced commercially to be used in oil fields. So it makes sense to capture waste CO2 and use it instead. (Perhaps this should be considered CO2 recycling rather than sequestration, however - I assume that CO2 dissolved in the oil comes back to the surface with the oil. Not that there's anything wrong with recycling - make less waste, use if for useful purposes instead. But it doesn't take the CO2 away forever.)

2) Pump the CO2 into coal. The methane that adsorbs onto the surfaces of coal has become a commercially important source of natural gas (especially in the San Juan Basin, just south of Durango). Traditionally, the methane is released by pumping water out of the coal. But carbon dioxide also adsorbs onto the surfaces of coal. Maybe CO2 could be used to enhance coal-bed methane production, too.

This technique is being tried in my backyard. If it works, it's got a lot of potential, because coal-bed methane and coal-burning power plants (as a source of carbon dioxide) can be very near one another. (In fact, there are currently two coal-fired power plants near Farmington, New Mexico.) I don't know much about the surface chemistry of coal, so I don't have a good sense of what factors could make this work or not.

3) Pump the CO2 into deep, salty formation water. This is the target of the experiment that Lee Allison described today. I'm not entirely certain of the characteristics of the ideal "saline formation" sequestration project. I think the idea is that a) the salty water is isolated from useable groundwater, probably by some kind of low-permeability cap (like a classic oil reservoir would have); and b) the salty water would make a good chemical buffer for the carbonic acid. I'm not sure of the chemistry of the buffering - this is where I wish that I remembered the complications that happen in the systems of carbonic acid, bicarbonate, and carbonate when there's something in the system other than calcite and carbon dioxide. (I'm guessing that the high concentration of dissolved solids helps buffer the system, since the focus isn't entirely on limestones.) I'm also not sure how the dissolution of carbon dioxide in water affects the potential for problems with increased pore fluid pressure. (Increasing the amount of fluid in rock can make rock break. If you want to get oil out of the rock, this is a good thing; if you want to keep carbon dioxide from escaping, I'm guessing that it would be bad. Unless you can make the reservoir rock more permeable without breaking the less permeable cap?)

And this doesn't include ideas about using carbon dioxide to speed the weathering of silicates. (I think that's partly what's going on with the suggestions to sequester carbon dioxide in basalt, for instance.)

So I'm not sure how to discuss the issue in intro classes. I think I need more information. I would like to tell them about the ideas that have been proposed, however - particularly because some are happening in our own backyard.

*Carbon is naturally locked in rocks like coal, oil shale, and limestones. We let it out when we burn oil, coal, or natural gas, or when we make cement. But natural processes don't remove carbon as fast as we burn it for energy. So if we want to use fossil carbon for energy, and we don't want to deal with the consequences of putting all that carbon dioxide in the atmosphere, we've got to do something to speed up the process.

Saturday, November 8, 2008

Geoblogger meet-up at AGU?

Lee Allison asked if there is going to be a geoblogger meet-up at AGU. I know that Christie and Brian are going to be there, and I think Ron is organizing a session and Julian submitted an abstract. And Andrew is local to the Bay Area. (There are also some pseudonymous bloggers who have mentioned being there. I'm not leaving you out on purpose - I'm just letting you choose what info you want the world to know.) I'm sure I'm leaving other people out, too.

I'm arriving Tuesday afternoon and leaving Thursday afternoon (and I really want to catch up with some of my former students!), so I don't have a lot of flexibility. But would anyone be interested in meeting for dinner on Wednesday night?

Teaching intro geoscience workshop at AGU

Earlier this week, I received this message from Anne Egger, who is co-organizing two sessions and a workshop at AGU in December. I'm going to be speaking in the second session (and I'm looking forward to the poster session as well - the posters look interesting, and I like poster sessions for pedagogy discussions), but I'm not going to be at the meeting in time for the workshop. I found this summer's workshop very useful, though, and I expect that the one-day version will also be great.

Teaching Introductory Geoscience in the 21st Century

As part of the Cutting Edge program, we are offering a 1-day workshop on teaching introductory geoscience on Sunday , December 14 , in San Francisco, the day before the AGU Fall meeting begins.Many faculty have introductory courses in their teaching repertoires, and those courses span a wide range of subject areas, including physical and historical geology, environmental science, oceanography, natural hazards, and courses that follow a regional or topical theme. This workshop will bring together faculty from a wide variety of institutional settings and backgrounds with the common goal of sharing ideas about improving the pedagogy and content of all of our introductory geoscience courses. The 1-day workshop both builds on and serves to disseminate the results of an identically-titled workshop that took place July 14-17, 2008.

Conveners: Cathy Manduca and Anne Egger

DEADLINE TO REGISTER: Friday, November 21
NOTE: You do not need to be registered for the AGU meeting to attend this workshop.

More information about the workshop can be found here:

To register, go here:

Goals and Format
During this 1-day workshop, we will explore the following topics

• How can we maximize the long-term impact of our introductory courses?
• How do we engage students in the real process of science even at the introductory level?
• What are some approaches to designing a new course or breathing new life into an existing course?
• How can we make activities we currently use in our courses more effective?
• How do we approach challenges like teaching large courses, courses with no lab component, or courses in urban settings with nary an outcrop in sight?

The workshop format will include plenary talks, large and small group discussions, and time for planning changes to your own course and activities. In addition, all participants will contribute to development of the online collection of introductory teaching activities for the classroom, lab or field. In doing so, workshop attendees will consider what makes effective activities and assignments and will review and make suggestions for improving submitted materials.

Thursday, November 6, 2008

Demography, geoscience jobs, and crystal-ball gazing

When I got the latest Geoscience Currents from AGI, I immediately printed it out and hung it on the wall in the geology majors' study room.

Here's why:

AGI collected information from a variety of groups that keep track of various employed geoscientists and graphed their membership by age. (They don't have information from any mining industry groups; SEG in this case is the Society of Exploration Geophysicists, not the Society of Economic Geologists.) Hydrologists are the only group that has significant numbers of 40-something geoscientists; my generation was not hired to work for the oil & gas industry.

I hung up the page because of this line from it: The majority of geoscientists in the workforce are within 15 years of retirement age. But after I hung it up, I wondered about the assumptions being made about future employment opportunities.

When I was a senior in college, I had The Conversation with my academic advisor: "What do you want to be when you grow up?" He suggested that I go to graduate school. His generation had been hired to educate the Baby Boomers, he said, and his generation was going to retire soon. There would be lots of academic jobs to replace people like him. If I went to grad school then, in 1989, I would get done just in time.

I did go straight to grad school, though I would have taken a job if I had found one. But when I graduated, jobs were hard to come by. I know a lot of talented geology grad students who left the field after their post-docs went nowhere. My advisor's generation did retire, yes, but there were many more grad students than there were retirements. And there weren't many jobs in industry, and the USGS wasn't hiring, and academic departments were being closed.

The situation for industry jobs now may be different. There are far fewer undergrad geology majors than there were in the early 1980's. The supply of young geologists may very well be lower than the demand.

But it's a matter of supply and demand, not of needing to replace the exact number of geologists who are about to retire. How many geologists will the oil & gas industry need for the next thirty years? What if oil production has peaked? What if concerns about global climate change combined with high oil prices drives a shift to different energy sources? How many geologists will oil & gas need during busts? How many will the mining industry need? (And what will they be mining?) My Magic Garnet Ball isn't clear enough to tell. (Stupid inclusions.)

I know that "the market" is taking a beating right now, but I still look to it for signals that industry really needs geologists. Are people being hired with bachelor's degrees? What are they making for salaries? Are companies offering to pay students to go to grad school, or do they expect students to prepare themselves for a job that may or may not be there in two or three years? Are PhDs with some industry experience getting new jobs when they are laid off (and how long does it take to find a new job)?

I've adjusted the things I cover in structural geology to try to fit the needs of students who might work in groundwater, in oil, or in mining. I want my students to be ready to take jobs if they are available. But I wonder whether we are being honest about the future. I can't predict the stock market... and geology jobs are as much at the mercy of economics as other jobs are.

Edit: Andrew at discussed a related article in GSA Today here. (The GSA Today article discusses the age distribution of GSA member, and has as a take-home message that my generation of geologists needs to take over leadership roles in geoscience organizations. The Structure/Tectonics Division of GSA has had multiple volunteers for leadership positions from my generation in the past two years, at least. My generation of academics is barely post-tenure, though, despite being old-school already. We're not used to people taking us seriously.)

Thursday, October 30, 2008

Spooky geology

Happy day-before-Halloween. (All Hallow's Eve Eve?)

I've got a ridiculous amount of candy (though I'm in town now, and I'm not calibrated for trick-or-treaters other than the Small Human). I've got a costume for the Small Human. I don't have a costume for myself, however. (Small Human wants me to go as a bat. Given today's stories about the causes of white-nose syndrome, though, I don't have the heart for it. Poor little guys.)

A few years ago, I encouraged my intro class to dress up as something geological. I forgot to do it this year (and it worked better when the class suggested the idea), but I got to wondering...

What would be the scariest possible geologic costume?

I think I would have to go with liquefaction. There's an earthquake, the ground turns to quicksand, buildings and people sink into the ground, and then the sand solidifies around you so you can't breath.

And then the dogs come out and eat your head.

(Images of the 1692 Port Royal earthquake from .)


I'm not sure exactly how the costume would work, though. I could encase myself in sandy plaster and stop breathing... but maybe that wouldn't be a good idea.

On second thought, maybe I'll go as some obscure geology jargon that deserves to be re-animated. Nothing like a good word to eat a brain.


Wednesday, October 29, 2008

Earthquake in Pakistan

BBC: Scores dead after Pakistan earthquake
Scientific American 60-second-science post

There were two moderately large (M6.4, M6.1) earthquakes within twelve hours:

The earlier one had an epicenter right beside a populated valley - Khanozai, Pakistan. (Unfortunately.)

The second one had an epicenter beneath some spectacular plunging folds (WOGE-worthy, except that I'm posting the picture out of turn):

Both earthquakes had similar focal mechanisms. North-south compression (along the India/Asia collision), earth-west extension, along a strike-slip fault (again, common in Asia - see Tapponier et al., 1982, for example). Based on the aftershock locations, I would guess the NW-striking solution is the real fault. I'm curious about the relationship of the seismogenic faults to the plunging folds, though. I don't have a quick explanation... and I'm just starting to talk about faults in class this week. I would love to show the Google Earth images, but the folds show up so well on the satellite images that I should be prepared to answer questions about them in a semi-coherent way.

The earthquakes are also right at the place where the folds near the plate boundary make a sharp bend:

(By the way, does the apparent strike of the fault line up with the boundary of that basin by Kandahar, Afghanistan? It's the brown area west of the earthquakes; I don't have the cities layer turned on in my image.)

I'm not sure how that affects the faulting, either.

Reference: Tapponier, P., Peltzer, G., Le Dain, A.Y., Armigo, R., and Cobbold, P., 1982, Propagating extrusion tectonics in Asia: new insights from simple experiments with plasticine: Geology, v. 10, p. 611-616.

Edit: There's discussion of landslide potential from these two earthquakes at Dave's Landslide Blog: post #1; post #2.

Thursday, October 23, 2008

Got a new science building? Want to tell me about it?

The science departments here are in a building phase. Chemistry got a new building a few years ago, biology is getting a new building right now... and just this morning, we learned that physics, engineering, and the geosciences have the go-ahead to start really planning a new building ourselves.

So now we want to know what cool things other institutions have done recently. If you know of a new science building (and especially a new geology, physics, and/or engineering building) from the past ten years, especially one that uses green building standards, make innovative pedagogy possible, or facilitates undergraduate research*, we'd like to talk to you (and maybe visit your building). (Has anyone taught with a Geowall, or learned with a Geowall? How about the new microscopy labs with digital cameras and computers, which make collaborative learning possible in optical mineralogy and petrology? Those are a few things that I know about, but I would like to know about what things are so new that I haven't heard about them, as well.)

You can contact me at my work e-mail (just google me - you'll find it) or at shearsensibility AT gmail DOT com.

*The president is interested in knowing what research universities do as well as knowing what undergrad institutions do. He wants to make sure we're thinking for the future, which is a good thing, since that's what planning's supposed to involve.

Wednesday, October 22, 2008

Making AGU plans

I'm going to AGU for the first time since 2000. I've tended to go to GSA instead, but AGU has been getting more and more interesting (even for someone who's primarily a geoscience educator rather than a researcher, at this point). In the past, AGU has seemed like a meeting for specialists, and if there wasn't a session on something I was actively involved in, the talks were difficult to follow. (I was completely lost by a talk about lightning that I saw on a whim eight years ago. No pictures. You know I'm a geologist... I go to talks to see the pretty pictures.)

I'm talking late (like 5:15 pm) on Wednesday. And that complicates things, because it's final exam week, and my exams are scheduled for Tuesday and Thursday. And flying in and out of Durango is time-consuming at best. I'm looking at giving my Structural Geology exam, then trying to get to the airport and get an early afternoon flight that will connect to San Francisco. And then... well, I can't realistically make it back in time for a 7:30 am Thursday intro exam or for my practical exam time for my sophomore mapping class. (Fortunately, the sophomores have to schedule individual times, so I've got flexibility there. The intro class... well, I can ask someone else to hand out the tests for me, I guess.)

I was planning to go for one day, max, because San Francisco is expensive and I've often felt out-of-place at AGU. But I'm wondering whether the conference has changed, and whether a hopeless generalist would be able to stay busy all through Thursday. (There are a number of structure sessions, even if I don't want to leave my broad area of expertise.) Those of you who go to AGU - would it be worth staying another day, to learn content for teaching (as opposed to keeping up with research related to mine)?

And are you going to AGU? Want to meet up? (That's a question both for old friends and for geobloggers.)

Edit: I've booked my flights, arriving late afternoon on Tuesday and leaving in the evening on Thursday. (There aren't actually red-eye flights to Durango, but there are flights leaving after 5 pm that connect to Durango. Wow.) So can we have a blogger get-together on Tuesday or Wednesday evening?

Monday, October 20, 2008

I've voted. Have you?

Colorado, like many other states, allows people to vote early, either by mail or at a special polling place. This year, the county clerks have been encouraging everyone to vote by early or by mail, because there is an incredibly long list of referendums, and they anticipate long lines on election day.

So I voted yesterday. (And the referendums really took forever to read.)

If you're voting by mail in Colorado, rumor has it that you need to put two stamps on the envelope or it will be returned. (That's what my local free weekly paper claims, at any rate.)

Now I just have to keep hanging up on robo-calls and push polls for a few more weeks. (Life in a swing state. Always exciting.)

Meanwhile, I've got to decide how to let students miss part (or all) of my field methods lab so they can stand in line. We're not allowed to campaign at work, but I don't think that excusing absences on election day is the same as campaigning.

(BTW, I am not at work now. Sitting at home and grading is working, but it doesn't count as state time if it's after 9 pm. And the computer is mine, not work's.)

Sunday, October 19, 2008

Web resources for teaching with Google Earth

I just got an e-mail from Barb Tewksbury (actually, two e-mails; I'm on two mailing lists) telling about some new pages that she has added to SERC's Cutting Edge websites. She's been using Google Earth in Structure, and she's added a portal to collections of Google Earth teaching ideas (and great locations).

Teaching map interpretation with Google Earth
A collection of Google Earth mapping locations

There are a number of other Google Earth activities on SERC, too.

Given the fun of Where on Google Earth, plus Ron's expertise with imagery and experience using Google Earth in the classroom, and Chris Rowan's geopuzzles, I thought that the geoblogosphere might have some great ideas to add to the collection. (As for me, I've got a new Google Earth extra credit assignment this term; I give the students a latitude and longitude, and they have to tell me about it. I'm still working out the bugs, though, and I've got this immense intro class project that I still need to finish uploading to SERC before I try to write up anything new.)

Edit: I forgot about Hypo-theses' post about draping undergrad mapping projects onto landscapes in Google Earth. Neat stuff. Check it out.

Thursday, October 16, 2008

Four Corners Geological Society talk tomorrow

I'm the speaker at this month's Four Corners Geological Society meeting in Durango. (The title is "Stitching plutons or magma-enhanced deformation: reaction textures, deformation, and thermal modeling from the aureole of the Victory Pluton, NE Vermont." I realize that 1) the title is way too long, and 2) at least one person reading this blog will wonder whether I have actually done anything in the past eight years. The answer, btw, is that I'm trying to wrap up some things related to the Vermont work, and I thought the FCGS members would be more interested in hearing about that than about pedagogy research.)

If anyone reading would like to come, it's in the basement of the College Union Building (the "Sub-CUB Pub"). There's a social hour at 5:30 pm, dinner at 6:30 pm, and the talk at 7:30 pm. Normally we take RSVP's for dinner, but there should be some extra space. (Let me know, though - I don't think there are many Durangoans reading this, but I could be wrong.) Dinner is $20, the talk alone is $2, and if you're a Fort Lewis College student, the talk is free.

Four Corners Geological Society website

(And to those wondering how I'm adjusting to moving all my old images to Powerpoint, the answer is... well, you know how you can scan slides? I had a work-study student doing that for some of mine, but they were scanned at the size of a postage stamp. When I opened the files, I felt kind of like the guys in Spinal Tap when the eighteen-inch Stonehendge set appeared. Fortunately, I've got new digital thin section photos, and maps and graphs that open in Illustrator, and thermal modeling results that open in Excel. But I had a moment where I wondered whether I could just do the entire thing with slides, except for the part that uses new data...)

Tuesday, October 14, 2008

Googling for reliable geoscience sites

Chris Rowan is better at Googling than I am. He know how to customize Google searches so they prioritize sites that he considers reliable, and he knows how to share his search engine with the world.

He's looking for suggestions for useful and reliable sites. (Think USGS-level reliability.) If you know of some that he's forgotten, please suggest them to him.

Monday, October 13, 2008

Analogies, analog modeling, and squashed chocolate

While I was away, Callan asked about geobloggers' favorite analogies. Several other people responded. I'm a week late to the party, but I want to play, anyway.

A few weeks ago, I bought a chocolate cookie from one of my former intro students at the local farmers' market.

"You like chocolate, don't you?" she asked.

"Ummm. Yeah." (I didn't have the cookie in my mouth quite yet, but I may have been drooling.)

"I remember you talking about it all the time in our class. Especially about leaving chocolate in a hot car or putting it in the freezer."

So when I came back from GSA, it was time to give my (one, tragically brief) lecture about rock deformation. (That's the sad thing about teaching Earth Systems Science. I can't spend weeks talking about my favorite things.) It's maybe a bad idea to try to explain one's entire specialty in a single lecture after spending week listening to experts talk about the newest, coolest stuff in one's field. In any case, I was having a harder time than usual distilling the subject into its most basic essences.

When I've only got one lecture to do all of structural geology, I spend most of my time talking about faults. Faults can have earthquakes; earthquakes can kill (or at least make life very unpleasant). But I try to explain that ductile deformation exists, and the whole bottom half of the continental crust (not to mention the mantle) deforms that way.

I don't try to explain ductile deformation with rocks. It's hard to imagine something as hard as a rock squishing, even when the rock looks like this:

Photo: disharmonic folds in marble below the Snake Range decollement

So I resort to describing other materials. Silly Putty is great for describing ductile behavior, but it doesn't explain how cold materials behave differently from hot materials. (Well, I don't think it does. I've never put my Silly Putty in the freezer.)

Chocolate, on the other hand, is perfect. Put a chocolate bar in the freezer overnight. When you take it out, you need a rock hammer (or some other implement of destruction) to break off pieces. Cold chocolate is brittle.

Leave the same chocolate bar in your car, though - not tonight, because it's cold out tonight, but maybe during the day tomorrow. Take it out. If it's still solid, it will probably bend in your hands without breaking. (It might have melted, in which case it's now igneous chocolate, which has its own appeal, but which messes up the analogy.) Warm chocolate bars are ductile.

I've used this explanation for years, and normally I get exactly the responses I want. And this year, the students described the cold chocolate just fine, but when we got to the warm chocolate bar...

"What kind of chocolate?" they asked.

I shrugged. "What kind of chocolate do you want?" I generally prefer dark chocolate, but milk chocolate will do, as well.

"How about a Snickers bar?"

I frowned. "You know, a Snickers bar is great in the field, especially if the bears don't eat it, but I think its behavior is a bit too complicated for this analogy."

"Ok, then, what about a Milky Way?"

The point was not getting across. "No, a Milky Way is still made of too many different things, with different behavior. I think we should make our model as simple as possible to begin with. Because, umm, we want to avoid edge effects or something." I am not a modeler myself, but I had just gotten back from GSA.

"Oh. You mean just a Hershey's bar?"

"Yes. Yes, a Hershey's bar will do."

"How about if it has almonds in it?"

"NO! Just a Hershey's bar."

I have a horrible feeling that the other students in the class will write very confusing essays about caramel, nougat, and almonds. Or at least that they will threaten to unless I feed them.

Edit: I almost forgot that I've seen an example of class experiments deforming candy: the deformation of Charleston Chews, used in Structural Geology classes by Arlo Weil from Bryn Mawr. It's a great experiment/demo/in-class exercise... but I'm told that the smell of the candy makes people feel sick. And I'm trying to get students to make positive associations with rock deformation. So maybe pure chocolate is better for the thought experiment.